Ultrasound sorting of weanling calves and identification of tenderness indicators

ABSTRACT

A method and system for determining meat quality in cattle is provided. In preferred embodiments the method comprises obtaining an ultrasound measurement of a cattle specimen between the 12 th  rib and 13 th  rib at weaning age. The ultrasound measurement is utilized to extrapolate a harvest quality parameter. Based on the harvest quality parameter, and preferably a yield grade, the specimen is categorized. Particularly preferred harvest quality parameters are ribeye area, fat thickness, intramuscular fat and ribeye shape. Methods for determining tenderness, stress and intramuscular fat are described and claimed.

TECHNICAL FIELD

The present invention is related to the use of ultrasound to sort calvesat weaning based on predicted meat quality at harvest. Morespecifically, this invention is related to an ultrasound method, andapparatus, which improves the sorting of calves and the ability topredict carcass meat quality, particularly the tenderness of the meat.

BACKGROUND

It has long been the desire of cattle producers to predict the eventualmeat quality of beef cattle at an early age. Particularly, it has beenthe desire to determine meat quality early enough to allow the cattleproducer to optimize the herd for maximum financial return.

Carcass measurement has long been practiced in the art. Carcass testingcan provide valuable information utilizing pattern recognitionprocedures to insure that the available meat is optimized. While carcassmeasurements are advantageous, it eliminates the possibility ofutilizing exemplary specimens in breeding programs or of extendingharvest time for maximum financial gain. Some specimens may return ahigher financial return if allowed to develop slightly longer or thefinancial return may be higher if slaughter is expedited. Any form ofcarcass testing eliminates further optimization of the financial returnor of meat quality. Exemplary references disclosing the use of carcassmeasurements include: U.S. Pat. Nos. 3,603,303; 4,099,420; 4,758,817;5,303,708; 6,099,473 and 5,079,951.

Presently, in the beef industry, ultrasound technology is not used toevaluate seed stock cattle for carcass merit until approximately oneyear of age. The prior thought has been that cattle needed to achieve atleast this level of physiological maturity to adequately evaluate meatquality. However, if seed stock cattle could be reasonably evaluated atthe time of weaning, substantial economic impact could result. There areno current methods in place to determine potential tenderness instanding cattle. The National Cattlemen's Beef Association (NCBA) hasidentified tenderness problems of beef as one of the major contributorsto customer dissatisfaction. The ability to determine potentialtenderness of a carcass via live animal ultrasound could tremendouslyenhance genetic selection and ultimately the uniformity of the beef.

It is now standard practice to fatten the entire herd of cattle prior toharvest. This is costly and could result in fattening of inferiorspecimens which could return a loss or insufficient profit to justifythe expense. The current methods of testing typically measure the sizeof the longissimus dorsi muscle as well as the internal and external fatcontent just prior to harvest. These methods are not applicable prior tothe full regiment of feed has been completed since these parameters area direct result of the feed program. Even if the size is optimum and thefat content is optimum the meat may still be tough. It would be a majoradvantage if the meat quality could be evaluated prior to the expense offeeding cattle for harvest.

Size measurement techniques, wherein the size or shape of thelongissimus dorsi muscle, or ribeye, is determined are legion in number.The size of the longissimus dorsi muscle relative to the fat thickness,or total weight, are correlated to meat yield but not necessarily meatquality parameters such as tenderness. Measurements of muscle size, orshape, utilizing ultrasound techniques are disclosed in U.S. Pat. Nos.3,496,764; 4,359,055; 4,359,066, 6,012,332; 5,520,183; 5,353,796;5,339,815; 5,960,105 and 5,914,825. These techniques are only usefuljust prior to harvest since the amount of fat is clearly a function ofthe feeding regiment and meat quality includes additional parameters.

Indirect methods of determining meat quality based on the fat content,or by correlation to a panel of human analyst, have been described yetthese are still not predictive of future meat quality parameters such astenderness. Exemplary disclosures are provide in U.S. Pat. Nos.5,685,307; 5,208,747 and 5,625,147.

The physical transducer, methods of insuring proper placement, andsignal processing procedures for standing cattle just prior to harvestare disclosed in U.S. Pat. Nos. 5,836,880; 5,872,314; 6,170,335;5,316,003; 5,573,002 and 6,167,759. None of the cited references canprovide a predictive measurement of meat quality early in the life cycleof the specimen. Specifically, there is not available in the art asystem which provides the ability to measure cattle at weaning topredict the future quality parameters such as tenderness.

Even with the advanced nature of the art there is still a desire topredict, preferably at weaning, the eventual tenderness of the meat.Heretofore, this has eluded those of exemplary skill in the art.

There has been a long felt desire in the art for a non-invasivemeasurement technique, and apparatus therefore, which will allow for thepredictive determination of meat tenderness and other properties relatedto meat quality thereby allowing for optimized financial return andimproved quality of the beef early in the life cycle of the cattle.

SUMMARY

It is an object of the present invention to provide a method and systemfor predicting meat quality of cattle early in the life cycle therebyincreasing the return at harvest.

It is another object of the present invention to provide a method fordetermining the quality of meat, specifically tenderness, prior toharvest. More preferably, the tenderness can be determined at weaningthereby allowing herd discrimination to be practiced.

It is yet another object of the present invention to provide a methodand system which can allow for accurate prediction of meat quality withstanding cattle thereby allowing exemplary specimen to be recognizedprior to harvest. A particular advantage is the ability to utilizeexemplary specimen in breeding programs which can increase the overallvalue of the herd and return on the investment.

These and other advantages, as will be realized from the teachingsherein are provide in a method for categorizing cattle by meat quality.The method comprises obtaining an ultrasound measurement of a cattlespecimen between the 12^(th) rib and 13^(th) rib at weaning age. Theultrasound measurement is utilized to extrapolate a harvest qualityparameter. Based on the harvest quality parameter, and preferably ayield grade, the specimen is categorized. Particularly preferred harvestquality parameters are ribeye area, fat thickness, intramuscular fat andribeye shape.

Another embodiment of the present invention is provided in a method forcategorizing cattle by meat quality. The method comprises obtaining anultrasound measurement of a cattle specimen at a location ofapproximately ¾ of the length of a longissimus dorsi muscle between the12^(th) rib and 1^(st) lumbar. Tenderness is determined based on theultrasound measurement and the specimen is categorized by thetenderness. In a particularly preferred embodiment the tenderness isdetermined by the angle of connective tissue deposition in a longissimusdorsi muscle. In another preferred embodiment the tenderness isproportional to the connective tissue thickness.

Yet another embodiment is provided in a process for predicting meattenderness in an animal. The process comprises the steps of a) obtaininga longitudinal ultrasound measurement of a longissimus dorsi muscle; b)determining the angle of the connective tissue in the longissimus dorsimuscle relative to the centerline of the animal; and c) assigning atenderness based on the angle of the connective tissue.

Yet another embodiment is provided in a system for predicting meattenderness wherein the system comprises an ultrasound system forobtaining an image of a longissimus dorsi muscle and a measurementdevice for determining an angle of connective tissue in the longissimusdorsi muscle from the image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of the system of the presentinvention.

FIG. 2 is a flow chart representing a preferred method of determiningquality parameters of cattle.

FIG. 3 is a partial cut-away perspective view of a conforming guidewhich has exemplary utility in the present invention.

FIG. 4 is a partial cut-away side view of the conforming guideillustrated in FIG. 3.

DETAILED DESCRIPTION

The invention will be described with reference to the drawings whereinsimilar elements are numbered accordingly.

An ultrasound system for measuring meat quality is illustratedschematically in FIG. 1. In FIG. 1, the specimen, 1, is in functionalcontact with an ultrasound transducer, 2. A pulse generator, 3,transmits a series of high voltage pulses which the ultrasoundtransducer, 2, converts to ultrasound pulses in the preferred frequencyrange of 3.0-7.5 MHz. Most preferably the transducer transmits at afrequency of approximately 3.5 MHz. The ultrasound pulses aretransmitted into the specimen, 1. Pulse generators are commerciallyavailable and not limited herein. While not limited thereto, aparticularly suitable pulse generator is an ALOKA Model SSD 500Vavailable from ALOKA USA. Transducers are commercially available and notlimited herein. While not limited thereto, a particularly suitabletransducer is a Model UST 5044 3.5 MHz also available from ALOKA USA.

It is most preferable to utilize a conductive fluid, 4, between thetransducer, 2, and the specimen, 1, to insure adequate transmittal ofultrasound waves. While not limited herein common conductive fluidsinclude water, vegetable oil and mineral oil. In a preferred embodiment,a conforming guide is employed as described further herein.

The transducer transmits ultrasounds and receives an echo, orbackscatter, of the ultrasound waves. The echo time and energy is basedon the composition of the material through which the ultrasoundtransits. The echo signal is related to boundary structures, tissuedensity and other factors as well known in the art. In the presentinvention it is most desirable to utilize B-mode ultrasound, alsoreferred to as brightness mode, which provide two dimensional images ofthe scanned field. A-mode ultrasound, also referred to as amplitudemode, provides a projected view and is less desirable due to thedifficulty associated with differentiating layers and particularly thethickness of individual layers. The echoed ultrasound wave is receivedby the transducer, 2. The transducer generates an output signal which isproportional to the echoed ultrasound wave. An receiver/amplifier, 5,receives the voltage pulse from the pulse generator, 3, and the outputsignal from the transducer, 2. The output signal from the transducer isamplified and output to an analog to digital converter (A/D converter),6. The digital signal is captured by a computer, 7. A storage device, 8,preferably integral to the computer, can store raw data directly fromthe A/D converter. A data processor, 9, determines properties of thesample from the digital data and transmits these properties to a displaydevice, 10.

Receivers, amplifiers and image capture devices, either as a singledevice or a combination of devices, are readily available from a varietyof commercial sources. While not limited thereto, an Imagination Model2019 image capture board available from Zedec Vision Systems iseminently suitable for demonstration of the invention as set forthherein. Analog to digital converters, computers, and data processors areall well know and widely available from commercial sources. The presentinvention is not dependent upon the selection of these devices. Whiledescribed herein as independent elements it is understood that a singlesystem can be utilized which comprises those elements necessary toaccomplish the task described without departing from the invention.While not limited thereto, an ultrasound system commercially availablefrom ALOKA USA, adapted to select the parameters of the image describedherein can be used to demonstrate the teachings of the presentinvention. Display devices are commercially available from many sources.Display devices include hard copy devices such as printers, and softcopy devices such as computer screens, monitors and the like. In oneembodiment the storage device, 8, is capable of storing digital datadirectly from the computer, 7. In another embodiment, the storage devicecan store the properties which have been determined from the digitaldata by the data processor, 9. Data storage devices are well known inthe art and not limited herein. Particularly preferred are storagedevices such as hard drives, magnetic or optical media, paper printouts,random access memory storage devices and the like.

A flow chart illustrating the procedure for determining meat quality isprovided in FIG. 2.

Prior to analysis the specimen is prepared at block 20. Preparationpreferably includes manual cleaning of the scanning site and applicationof conductive fluid. It is most preferable to remove surface hair fromthe scanning site to insure adequate contact between the transducer andthe skin of the specimen. After sample preparation, 20, a choice is madebetween a cross-sectional exam or a longitudinal exam, at block 21.

If a cross-sectional exam is chosen, initiating with block, 22, thetransducer is placed in the proper position perpendicular to longissumusdorsi muscle and the vertebrae and between the 12^(th) and 13^(th) ribat block 23. The position allows for a cross-sectional view of thelongissimus dorsi muscle.

A signal is generated, at block 24, which causes the transducer to emitan ultrasound signal, preferably at approximately 3.5 MHz. Theultrasound signal is back scattered from the specimen with backscattered times and intensities based on the anatomical featurestherein. The back scattered, or echoed, signal is received by thetransducer. After acquiring a signal a counter is advanced at block 25.If three landmark samples have been acquired, as indicated at block 26,the signal processing is initiated at block 27. Otherwise, additionalreadings are recorded.

Cross-sectional image capture allows for determination of fat thickness(FT), ribeye area (REA) and a ribeye shape score (RES).

The ribeye area is determined, at block 28, by the cross sectionalimaging measurements taken at the three landmarks in the longissimusmuscle image taken between the 12^(th) and 13^(th) rib location. Thethree landmarks utilized are the upper fat line between the longissimusdorsi muscle and the back fat, the vertabrae process and the junction ofthe lateral portion of the longissimus dorsi muscle and the intercostaljunction. If the three landmark areas are not present the image is notaccepted for interpretation. The processor also calculates the 12^(th)through 13^(th) rib back fat thickness (FT) from the ultrasoundcross-section between the 12^(th) and 13^(th) rib location. The systemdetermines FT, at block 29, based on identification of the distancebetween the second interface line from the top of the image to thebottom of the third interface line. This measurement may be used as anindicator of yield grade in weaned calves, yearling cattle, and fedcattle to aid in determining appropriate management level and tovalidate stress and performance. The system also calculates longissimusmuscle circumference which is also referred to as ribeye shape (RES), atblock 32, to determine area, muscle depth and muscle length based on across-reference REA determination. The REA, FT and RES are reported atblock 30. The RES of weanling age calves is a useful parameter forpredicting the final yield grade potential and calves may be rankedaccording to the RES. The FT, REA and RES reports can be stored in aretrievable database, as is common with computers, printed or displayedon a monitor. It is most preferred that the FT, REA and RES reports bedisplayed on a monitor at chute side to allow for instant decisions. Itis also preferred that the FT, REA and RES be stored, or printed, suchthat a record can be maintained as would be understood to be desirable.It would be apparent that the processor allows additional informationinput including a specimen identifier, weight, age, and other parameterstypical in the raising and maintaining of beef cattle.

If the measurement is complete, at block 31, the process is completed atblock 43. Otherwise, additional exam types can be initiated at block 21.

If a longitudinal exam is requested, as indicated at block 33, thetransducer is repositioned at block 34 such that a longitudinal image ofthe longissimus muscle can be captured between the 12^(th) rib and1^(st) lumbar vertebrae. A signal is generated at block 35 and image iscaptured at block 36. It is most preferably that at least two datapoints be acquired, as indicated by the counter, at block 37, and testblock, 38. The system preferably determines landmarks for obtaining asuitable image. Preferably at least two separate images are captured atblock 36 from separate locations. The signal is processed at block 39wherein the IMF is determined through averaging the values from eachlocation for pixel density and texture at block 40. In a preferredembodiment a minimum of two separate IMF images are required before acalculation can be conducted.

A determination of tenderness (TEND) is preferably conducted at the samesite as the calculation of IMF at block 41. A longitudinal ultrasonicimage of the longissimus dorsi is utilized to determine tenderness. Atenderness score based on the angle of connective tissue deposition inthe longissimus dorsi muscle and from the connective tissue density. Ithas been determined that the angle of connective tissue deposition iscorrelated to the angle of connective tissue in the longissimus dorsimuscle relative to the hypothetical plane through the vertebrae andcenterline of the specimen. For example, a connective tissue depositionangle of 0° would indicate connective tissue that is parallel to theplane through the centerline of the specimen and a connective tissuedeposition angle of 90° would indicate connective tissue that isperpendicular to the plane. In actual specimen it has been determinedthat the angle of deposition ranges from approximately 15° toapproximately 70° with tenderness decreasing with an increase in theangle of connective tissue deposition. In the present invention aspecimen with connective tissue deposition angle of less thanapproximately 27° would yield the most tender meat and could becharacterized as, for example, “tender”. A specimen with a connectivetissue deposition angle of approximately 27° to approximately 40° wouldyield the less tender meat and could be characterized as, for example,“acceptable”. A specimen with a connective tissue deposition angle ofgreater than approximately 40° would yield the least tender meat andcould be characterized as, for example, “tough”. Other methods ofcategorization could be utilized as would be apparent to one of ordinaryskill in the art including reporting the deposition angle of connectivetissue as the tenderness indicator.

The connective tissue thickness, or density, has also been determined tobe a factor in tenderness of the meat from a harvested animal. Inpractice, the connective tissue has been determined to range fromapproximately {fraction (1/32)}″ thick to approximately {fraction(5/16)}″ thick with the tenderness of the meat decreasing withincreasing connective tissue thickness. Therefore, a specimen with aconnective tissue density of less than approximately ⅛″ would yield themost tender meat, a specimen with connective tissue density ofapproximately ⅛″ to approximately {fraction (7/32)}″ would be lesstender and a specimen with a connective tissue density of more than{fraction (7/32)}″ would be least tender.

It is most preferred that the measurement for tenderness be determinedat a location of approximately ¾ of the length (cranial to caudal) onthe longissimus dorsi muscle at the 12^(th) rib to 1^(st) lumbarlocation.

After tenderness is determined the IMF, STRESS and TEND are reported atblock 42.

STRESS is determined based on the consistency of the pixel densitythrough the upper portion of the longissimus dorsi muscle. While notlimited to any theory it is postulated that the pixel density, observedas a black area in the ultrasound image, increases with inferior diet.It is observed, through experimentation, that the larger the black area,representing unresolved image, the tougher the meat after harvest.Therefore, specimen with no black image area in the upper region of thelongissimus dorsi muscle would be predicted to be the most tender afterharvest. In practice, a specimen with a black area in the ultrasoundcorresponding to approximately the upper 10% of the longissimus dorsimuscle is considered to be low stress, or assigned a stress area level1. A specimen with a black area in the ultrasound corresponding toapproximately the upper 20% of the longissimus dorsi muscle isconsidered to be medium stress, or assigned a stress area level 2. Aspecimen with a black area in the ultrasound corresponding approximatelyto the upper 30%, or higher, of the longissimus dorsi muscle isconsidered to be high stress, or assigned a stress area level 3.

Echogenicity of the connective tissue can be enhanced through the use ofcommercially available neuro-networking and image enhancementsubroutines without departing from the scope of the present invention.

Information derived from the REA, RES, FT, IMF, STRESS and TENDdeterminations are used to calculate predicted yield grade to be used infeedlot applications. A lower yield grade would indicate a specimen witha higher percentage of high quality meat per pound of specimen. A higheryield grade would indicate a lower percentage of high quality meat perpound of specimen. While not limited herein, the yield grade isdetermined based on the quality parameters REA, RES, FT, IMF, STRESS andTEND. A skilled artisan can provide a yield grade by combining theseparameters with, or without, weighting factors based on the marketconditions at the time of use or standards which could be establishedfor consistency. At the time of the ultrasonic measurement a body weightfor each animal will be entered. The calculated body fat and REA alongwith constants for estimated dressing percentage and kidney, pelvic andheart fat (KPH) are also used to derive predicted yield grade. Real timecalculations and display of potential yield grade and quality grade canallow for chute side selection decisions.

The transmittal and receipt of ultrasound signal is preferably done withas high of a fidelity as possible to avoid spurious results andanomalies. More particularly the modulation transfer function of signalcapture is preferably as close to unity as possible given the realisticconditions under which the measurement must be taken and the rapidity ofmeasurements required in a standard operation. Towards this goal apreferred conforming guide is illustrated in FIG. 3.

In FIG. 3, the conforming guide generally represented at 100, is shownin partial cut-away view. The conforming guide comprises a collar, 101,which is rectangular and adapted to tightly receive the transducer inthe central cavity, 102. The collar, 101, comprises an arch, 103, oneach side which approximately conforms to the shape of the back of aspecimen. A pliable seal, 104, receives the collar. As the conformingguide is brought into contact with the specimen the pliable seal, 104,conforms to the contour of the back of the specimen thereby forming aseal there between. An optional lip, 105, provides a convenient grip onthe contour guide. The collar, 101, is preferably constructed of nylondue to the low cost, ready availability and ease of machining. Thepliable seal, 104 is preferably constructed of Superflab Bolus availablefrom Mick Radionuclear Instruments. Other pliable materials can beemployed. It is most preferable that the pliable seal be easilyconformed to the contour of the specimen yet resilient enough that theoperator does not have to wait for a subsequent measurement while thepliable seal relaxes to an expanded state. The conforming guide can beutilized with, or without, a conductive fluid. The conforming guide ispreferably used during a cross-sectional measurement but is preferablynot used with a longitudinal measurement.

The conforming guide is shown in partial cutaway side view in FIG. 4.The dimensions of the conforming guide are chosen based on the size ofthe specimen and the size of the transducer. In a particularly preferredembodiment the collar is approximately 1.625 inches wide byapproximately 9.5 inches long and approximately 1.75 inches high at theends. The walls of the collar are preferably approximately 0.25 inchesthick. The cavity is preferably approximately 9 inches long and 1.125inches wide. The pliable seal is preferably 1.25 inches high andapproximately 0.25 inches thick for the preferred material.

For the purposes of the present invention cattle are considered weanedat the point when the mother no longer supplies food and the animal ison feed exclusively. This is typically 195-215 days after birth and morepreferably 200 to 210 days after birth. Most preferably, the cattle areweaned at 205 days after birth. The age at which a specimen is harvestedis preferably 12 to 19 months. Between the weaning and harvesting thecattle are placed on a feeding program to enhance the yield of meat.

The present invention is specifically intended to be used with acomputer wherein layer, and their thicknesses, are determined bycomputer algorithms. While not preferable, the present invention can berealized by human techniques such as by measuring a layer thickness froma monitor or from a hard copy printout of the image.

Experimental Results

A total of 97 weaned steers, randomly selected from a common herd, weremaintained in a Calan Gate Individual Feeding System so that individualfeed consumption could be recorded. All steers were ultrasonicallyscanned at weaning and at 30-day intervals up to the time of harvest.Data were collected for FT, REA, RES and IMF. Time of harvest wasdetermined by FT as measured at the 12^(th) rib location, with the endpoint at 10 mm. At harvest, following a 48 hour chill, all carcasseswere evaluated for quality grade and yield grade and actual carcassmeasurements were obtained for BF, REA, RES and IMF.

Data were analyzed to determine the ability of the system to accuratelycalculate ultrasound carcass measurements. Correlation coefficients wereused to determine the degree of relationship between calculatedestimates, Critical Vision software estimates and actual carcass datameasurements were used as comparisons. Critical Vison software isavailable from Critical Vision Incorporated, Atlanta Ga. Pearsoncorrelation coefficients from the sample comparing the REA determined bythe inventive system with that calculated by Critical Vision waspositive and significant (r²=0.90, p<0.05). The correlation between thecalculation of REA with the inventive system, measured five days priorto harvest, and actual carcass REA, measured after a 48 hour chill, wasalso highly significant and positive (r²=0.84, P<0.01). The correlationbetween the estimate of REA by Critical Vision software and actualcarcass REA was less reliable than the inventive system (r²=0.74,p<0.01). These results indicate that the inventive system, utilizingrecognition of image landmarks, is superior to currently availablesoftware.

Ribeye score (RES) was determined utilizing ultrasound at weaning andagain at the end of the feeding phase. For an accurate estimate of REA,the RES must be consistent as the animal grows and develops. The degreeof correlation between RES at weaning and RES at the end of the feedingphase was significant and positive (r²=0.62, p<0.05).

To determine the predictability of carcass quality grade, calves werescanned at weaning and a predicted quality grade was assigned at thatpoint based on estimates of IMF by the inventive system. Just prior toharvest, ultrasound IMF estimates were repeated. Correlationcoefficients between the quality grade predicted at weaning and harvesttime ultrasound IMF were significant and positive (r²=0.62, p<0.05).

A separate comparison of tenderness predictability was undertaken on 97steers. A tenderness score was assigned utilizing a longitudinalultrasound image of the longissimus at the 12^(th) rib location atenderness score was assigned in accordance with the inventive system.At harvest, a core sample was obtained from the 12^(th) rib locationfrom each steer. Each sample was cooked to the same degree of donenessand shear force estimates of tenderness were obtained by theWarner-Bratzler shear force measurement. The correlation coefficient wassignificant and positive (r²=0.72, p<0.05).

The invention has been describe with emphasis directed to the preferredembodiments. It would be apparent from the description herein thatvarious embodiments could be developed without departing from the scopeof the invention. Alternate methods of construction, operation and usecould also be employed without departing from the scope of the inventionwhich is set forth in the claims which follow.

What is claimed is:
 1. A process for predicting meat tenderness in ananimal comprising the steps of: obtaining a longitudinal ultrasoundmeasurement of a longissimus dorsi muscle of said animal; determining anangle of connective tissue in said longissimus dorsi muscle relative toa centerline of said animal; and assigning a tenderness grade based onsaid angle of connective tissue wherein said tenderness grade comprises:a first grade wherein said angle is less than approximately 27°; asecond grade wherein said angle is at least approximately 27° toapproximately 40°; and a third grade wherein said angle is greater thanapproximately 40°.
 2. A process for predicting meat tenderness in ananimal comprising the steps of: obtaining a longitudinal ultrasoundmeasurement of a longissimus dorsi muscle of said animal; determining anangle of connective tissue in said longissimus dorsi muscle relative toa centerline of said animal; and assigning a tenderness grade based onsaid angle of connective tissue wherein said angle is determined at alocation of approximately ¾ the length of a longissimus doris musclebetween the 12^(th) rib and 1^(st) lumbar.